When maintenance must be performed on the roof support truss of an industrial building, as when the truss must be sandblasted and painted, it is desirable to perform the maintenance without disturbing the industrial operation being performed on the work floor below. For example, in a paper mill and in other industrial processes where a substantial amount of moisture is generated within the building the roof trusses and other overhead structures deteriorate rapidly, and it is necessary to sandblast and paint the roof trusses, etc., but it is also desirable to maintain the manufacturing operation on the work floor below while the maintenance operation is being performed. In order to sandblast and paint the roof trusses while continuing the manufacturing operation below, it is desirable to physically separate the roof trusses from the manufacturing equipment below so that the humid environment of the manufacturing process is isolated from the roof trusses, and so that the sand and paint used on the roof trusses are not allowed to fall into the manufacturing process. Also, it is necessary to provide a stable support for the workmen and their equipment as they work about the truss, etc.
In the past, in order to provide a temporary floor structure that supports the workmen about the roof support truss and which forms a barrier between the overhead truss and work space below, cables have been stretched from one side to the other of an industrial building to form a support lattice and plywood panels have been placed on the cables to form a suspended floor surface immediately beneath the roof truss. Usually, the plywood panels were taped to one another along their abutting edges to hold them in place and to cover the cracks between the panels and vinyl sheets or other air impervious sheet material was laid across the plywood panels so as to form a seal on top of the plywood panels. It is important that the suspended floor be relatively thin so that the cranes and other tall structures used in the manufacturing process below can continue to function without impediment from the temporary suspended floor.
During the sandblasting and painting of a roof truss, a substantial amount of sand and debris accumulates on the suspended floor and the sand together with the workmen and their equipment must be supported sufficiently to avoid injury or spilling of sand, etc. the plywood panels placed in the suspended floor tend to "work" or move with respect to one another during the cleaning and painting process, sometimes failing to properly support the sand and the workers and their equipment, and the plywood panels tend to warp and otherwise deteriorate due to moisture from the manufacturing process carried on below the suspended floor and due to abrasion, impact and other wear and to environmental conditions as they are used in the suspended floor structure and due to handling between cleaning and painting sites. The deterioration of the plywood panels increases the hazard to the workers that work on the suspended floor, but the contractor occasionally uses damaged plywood panels when it is inconvenient to acquire replacement panels. Also, the working of the plywood panels with respect to one another tends to damage the tape and sheet material, creating a hazard for the workmen and perforating the seal between the roof support truss and the work floor below.